Perfecting printer and method for controlling double-face printing operation thereof

Abstract

A perfecting printer for performing a double-face printing operation of printing images on obverse and reverse faces of at least one sheet on the basis of a series of print data input from an external device and a method for controlling the double-face printing operation of the printer. The perfecting printer includes a page memory having an empty area for storing a series of print data for the obverse and reverse faces of the sheet input from external device, and a control unit for judging as to whether the empty area is no longer available in the page memory while the series of print data are being stored into the page memory and forcibly printing print data for the obverse face of the sheet on the sheet when it is judged that the empty area is no longer available in the page memory and that only the print data for the obverse face of the sheet are completely stored in the page memory.

What is claimed is 
     
       1. A perfecting printer for printing images on obverse and reverse faces of at least one sheet according to a series of print data including first print data and second print data to be printed on obverse and reverse faces of the sheet, respectively, the print data being an input from an external device, comprising: memory means having an empty area for successively storing the series of the print data input from the external device;   printing means for printing the first and second print data stored in said memory means on the obverse and reverse faces of the sheet, respectively;   judging means for judging as to whether the empty area is no longer available to store one of the first and second print data while the series of the print data are being stored into said memory means; and   control means for controlling said printing means to print the first and second print data on both of the obverse and reverse faces of the sheet, respectively, when the first and second print data are completely stored in said memory means, and to forcibly print only the first print data on one of the obverse and reverse faces of the sheet when said judging means judges that the empty area is no longer available for storing the second print data and when the first print data is completely stored in said memory, said control means further including clearing means for clearing the first and second print data stored in said memory means when both of the first and second print data are printed, and for clearing only the first print data stored in said memory means when the first print data and a part of the second print data are stored in said memory means and said empty area is no longer available for storing a remainder of said second print data, the first print data is cleared after being printed, and then the remainder of the second print data is store after forcibly printing the first print data on the obverse face of the sheet.   
     
     
       2. A perfecting printer as claimed in claim 1, wherein said memory means includes a page memory for storing the series of the print data therein while sectioning the series of the print data into plural blocks, and an input buffer for temporally storing the series of the print data before the series of the print data are stored in said page memory. 
     
     
       3. A perfecting printer as claimed in claim 2, wherein said printing means comprises a character generator for generating bit patterns corresponding to the blocks of print data stored in said page memory one by one, and a printing unit for successively printing images corresponding to the bit patterns on the obverse and reverse faces of the sheet one by one. 
     
     
       4. A perfecting printer as claimed in claim 1, wherein said control means controls said printing means to make the reverse face of the sheet a blank face. 
     
     
       5. A perfecting printer as claimed in claim 1, further comprising sheet reversing means having a sheet reversing path for passing the sheet therethrough to reverse the sheet. 
     
     
       6. A perfecting printer as claimed in claim 4, wherein when said judging means judges that the first and second print data are completely stored in said memory means, said control means controls said sheet reversing means to pass therethrough the sheet after the first print data has been printed. 
     
     
       7. A perfecting printer as claimed in claim 4, further comprising sheet discharging means for discharging the sheet to an outside, of said printer, and wherein when said judging means judges that the empty area is no longer available for storing the second print data, said control means controls said reversing means not to be driven and controls said sheet discharging means to discharge the sheet to the outside side after the first print data has been forcibly printed. 
     
     
       8. A perfecting printer as claimed in claim 1, wherein said memory means stores the first and second print data therein in this order. 
     
     
       9. A method of controlling a double-face printing operation of a perfecting printer including a page memory having an empty area for storing a series of print data including first print data and second print data to be printed on obverse and reverse faces of at least one sheet, respectively, and a control unit for controlling a printing operation of the printer according to the series of the print data, comprising the steps of: storing the series of the print data into the page memory while sectioning the series of print data into plural blocks;   judging as to whether the empty area is no longer available to store one of the first and second print data while the series of the print data are being stored into the page memory;   printing the first and second print data on both of the obverse and reverse faces of the sheet, respectively, when the first and second print data are completely stored in the page memory, or forcibly printing only the first print data on one of the obverse and reverse faces of the sheet when said judging step judges that the empty area is no longer available for storing the second print data and when the first print data is completely stored in the page memory; and   clearing the first print data stored in the page memory after the forcible printing, and storing the second print data completely in the page memory.   
     
     
       10. A perfecting printer as claimed in claim 9, further comprising a second step of judging as to whether entire print data for both of the obverse and reverse faces of a sheet are completely stored in the page memory, and printing the entire print data on the obverse, and reverse faces of the sheet if said second judging step judges that the entire print data are completely stored in the page memory, thereby performing a double-face printing operation. 
     
     
       11. A perfecting printer as claimed in claim 9, further comprising a step of reversing the sheet after the first print data has been printed when said judging step judges that the empty area is no longer available to store one of the first and second print data. 
     
     
       12. A perfecting printer as claimed in claim 9, wherein said storing step comprises a step of storing the first and second print data into the page memory in this order.